Using an implementation science framework, this study examines the impact of a multicomponent professional development (PD) approach implemented by internal peer coaches on early intervention providers' use of Family Guided Routines-Based Intervention. The experimental study used a single-case multiple baseline design across participants, replicated in three sites with early interventionist (EI) providers (n = 9) and families with infants and toddlers (n = 18) in U.S. community-based Part C programs. Data indicate a functional relation between the multicomponent PD approach and EIs' use of the intervention. A between-case standardized mean difference effect size was used to confirm the results of the visual analysis. The implications for the use of implementation science frameworks to build competency drivers within early intervention systems are discussed.